Method and device for the low-temperature separation of air at variable energy consumption
First Claim
1. A method for variably obtaining a pressurized-gas by means of low-temperature separation of air in a distillation column system comprising a high-pressure column and a low-pressure column, said method comprising:
- compressing the entire feed air in a main air compressor to a first pressure, which is at least 4 bar higher than an operating pressure of the high-pressure column,cooling a first partial stream of the feed air compressed in the main air compressor to a first intermediate temperature in a main heat exchanger, and work expanding the first partial stream in a first air turbine to form an expanded first partial stream,introducing at least a first part of the expanded first partial stream into the distillation column system,further compressing a second partial stream of the feed air compressed in the main air compressor to a second pressure, which is higher than the first pressure, in a first booster air compressor driven by the first turbine, cooling the second partial stream in the main heat exchanger, and subsequently expanding the second partial stream and introducing the expanded second partial stream into the distillation column system,removing a first product stream in liquid form from the distillation column system and increasing the pressure of the first product stream to a first product pressure,evaporating or pseudo-evaporating and warming the first product stream in the main heat exchanger,obtaining warmed first product stream as a first pressurized-gas product,compressing a first process stream, containing at least 78 mol % of nitrogen, in a multi-stage compressor from an inlet pressure to a final pressure,wherein the multi-stage compressor is a nitrogen product compressor andwherein the first process stream is a first gaseous nitrogen stream from the low-pressure column,said method further comprisingin said first operating mode, obtaining a first amount of said first pressurized-gas product,in said second operating mode, obtaining a second amount of said first pressurized-gas product, which is smaller than the first amount first pressurized-gas product,in the first operating mode, obtaining a second process stream which is a first gaseous stream from the high-pressure column and contains at least 78 mol % of nitrogen, and wherein no amount or a first amount of the second process stream is mixed with the first process stream downstream of a first stage of the multi-stage compressor and, with the first process stream, is compressed in the multi-stage compressor, andin the second operating mode, a second amount of the second process stream is compressed in the multi-stage compressor, wherein said second amount of the second process stream is greater than the amount of the second process stream compressed in the multi-stage compressor in said first operating mode.
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Abstract
A method and a device used to variably obtain a compressed-gas product by means of the low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of high-pressure column nitrogen is compressed in a nitrogen compressor and in the second operating mode, a second, larger amount is compressed in the nitrogen compressor.
6 Citations
21 Claims
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1. A method for variably obtaining a pressurized-gas by means of low-temperature separation of air in a distillation column system comprising a high-pressure column and a low-pressure column, said method comprising:
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compressing the entire feed air in a main air compressor to a first pressure, which is at least 4 bar higher than an operating pressure of the high-pressure column, cooling a first partial stream of the feed air compressed in the main air compressor to a first intermediate temperature in a main heat exchanger, and work expanding the first partial stream in a first air turbine to form an expanded first partial stream, introducing at least a first part of the expanded first partial stream into the distillation column system, further compressing a second partial stream of the feed air compressed in the main air compressor to a second pressure, which is higher than the first pressure, in a first booster air compressor driven by the first turbine, cooling the second partial stream in the main heat exchanger, and subsequently expanding the second partial stream and introducing the expanded second partial stream into the distillation column system, removing a first product stream in liquid form from the distillation column system and increasing the pressure of the first product stream to a first product pressure, evaporating or pseudo-evaporating and warming the first product stream in the main heat exchanger, obtaining warmed first product stream as a first pressurized-gas product, compressing a first process stream, containing at least 78 mol % of nitrogen, in a multi-stage compressor from an inlet pressure to a final pressure, wherein the multi-stage compressor is a nitrogen product compressor and wherein the first process stream is a first gaseous nitrogen stream from the low-pressure column, said method further comprising in said first operating mode, obtaining a first amount of said first pressurized-gas product, in said second operating mode, obtaining a second amount of said first pressurized-gas product, which is smaller than the first amount first pressurized-gas product, in the first operating mode, obtaining a second process stream which is a first gaseous stream from the high-pressure column and contains at least 78 mol % of nitrogen, and wherein no amount or a first amount of the second process stream is mixed with the first process stream downstream of a first stage of the multi-stage compressor and, with the first process stream, is compressed in the multi-stage compressor, and in the second operating mode, a second amount of the second process stream is compressed in the multi-stage compressor, wherein said second amount of the second process stream is greater than the amount of the second process stream compressed in the multi-stage compressor in said first operating mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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10. A device for variably obtaining a pressurized-gas by low-temperature separation of air, said device comprising:
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a distillation column system having a high-pressure column and a low-pressure column, a main air compressor for compressing the entire feed air to a first pressure, which is at least 4 bar higher than an operating pressure of the high-pressure column, a main heat exchanger, means within the main heat exchanger for cooling down a first partial stream of the feed air compressed in the main air compressor to an intermediate temperature, a first air turbine for work-expanding the first partial stream removed from the main heat exchanger, means for introducing the expanded first partial stream into the distillation column system, a first booster air compressor for further compressing a second partial stream of the feed air compressed in the main air compressor to a second pressure, which is higher than the first pressure, wherein the first booster air compressor is driven by the first turbine, is recompressed, means in the main heat exchanger for cooling the further compressed second partial stream, means for expanding the second partial stream removed from the main heat exchanger, and introducing the second partial stream into the distillation column system, means for removing a first product stream in liquid form from the distillation column system, and means for increasing the pressure of the first product stream to a first product pressure, means in the main heat exchanger for evaporating or pseudo-evaporating and warming the first product stream under the first product pressure, means for obtaining the first product stream as a first pressurized-gas product, a multi-stage compressor for compressing a first process stream, containing at least 78 mol % of nitrogen, from an inlet pressure to a final pressure, wherein the multi-stage compressor is a nitrogen product compressor and wherein the first process stream is a first gaseous nitrogen stream from the low-pressure column, means for mixing a second process stream, containing at least 78 mol % of nitrogen, with the first process stream downstream of the first stage of the multi-stage compressor, wherein the second process stream is a first gaseous nitrogen stream from the high-pressure column, means for switching over between a first operating mode and a second operating mode, wherein in the first operating mode, a first amount of first pressurized-gas product is obtained, wherein in a second operating mode, a second amount of first pressurized-gas product, which is smaller than the first amount, is obtained and the means for switching over between the first operating mode and the second operating mode permitting in the first operating mode, compressing no amount or a first amount of the second process stream in the multi-stage compressor from an inlet pressure to a final pressure and in the second operating mode, compressing a second amount of the second process stream, which is greater than the amount of the second process stream compressed in the first operating mode, in the multi-stage compressor.
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Specification